Less Remineralized Carbon in the Intermediate‐Depth South Atlantic During Heinrich Stadial 1
Less Remineralized Carbon in the Intermediate‐Depth South Atlantic During Heinrich Stadial 1
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DOI：
10.1029/2018pa003537
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发表时间：
2019-07
影响因子：
3.5
通讯作者：
M. Lacerra;D. Lund;G. Gebbie;D. Oppo;Jimin Yu;A. Schmittner;N. Umling
中科院分区：
文献类型：
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作者：
M. Lacerra;D. Lund;G. Gebbie;D. Oppo;Jimin Yu;A. Schmittner;N. Umling
最后一次冰川消退(~20-10KYR BP)的特征是地球气候状态发生了重大变化，当时全球平均地表温度上升了~4℃，大气CO2浓度增加了~80ppmv。模型模拟表明，大气二氧化碳最初上升30ppmv可能是由于生物泵效率降低或深海富碳水域上升流增强所致。在这里，我们使用从西南大西洋1,100米水深采集的岩芯中采集的海底有孔虫B/Ca(代表深水[CO32−])来评估这些假设。我们的结果表明，在假设碱度没有显著变化的情况下，Heinrich Stial 1早期的[CO32−]增加了22±2μ摩尔/公斤，或Σ二氧化碳减少了约40μ摩尔/公斤。我们的数据表明，在Heinrich Stial 1期间，再矿化磷酸盐下降了约0.3Mol/kg，相当于该位置现代再矿化信号的40%。由于示踪剂反演结果表明，核心位置的再矿化磷酸盐反映了次南极出口生产的综合效应，因此我们的结果表明，南大洋大西洋部分的生物生产力在冰川消融早期降低，导致大气二氧化碳最初的上升。
The last deglaciation (~20–10 kyr BP) was characterized by a major shift in Earth's climate state, when the global mean surface temperature rose ~4 °C and the concentration of atmospheric CO2 increased ~80 ppmv. Model simulations suggest that the initial 30 ppmv rise in atmospheric CO2 may have been driven by reduced efficiency of the biological pump or enhanced upwelling of carbon‐rich waters from the abyssal ocean. Here we evaluate these hypotheses using benthic foraminiferal B/Ca (a proxy for deep water [CO32−]) from a core collected at 1,100‐m water depth in the Southwest Atlantic. Our results imply that [CO32−] increased by 22 ± 2 μmol/kg early in Heinrich Stadial 1, or a decrease in ΣCO2 of approximately 40 μmol/kg, assuming there were no significant changes in alkalinity. Our data imply that remineralized phosphate declined by approximately 0.3 μmol/kg during Heinrich Stadial 1, equivalent to 40% of the modern remineralized signal at this location. Because tracer inversion results indicate remineralized phosphate at the core site reflects the integrated effect of export production in the sub‐Antarctic, our results imply that biological productivity in the Atlantic sector of the Southern Ocean was reduced early in the deglaciation, contributing to the initial rise in atmospheric CO2.